aInstituto de Ciencias Agrícolas, Universidad Autónoma de Baja California, Blvd. Delta s/n, Ejido Nuevo León, Baja California, México, 21705.
bUnidad Académica Multidisciplinaria Agronomía y Ciencias, Universidad Autónoma de Tamaulipas, Ciudad Victoria, Tamaulipas, México, 87149.
cCentro Universitario UAEM Temascaltepec, Universidad Autónoma del Estado de México, Temascaltepec, Estado de México, México, 51300.
*Corresponding author e-mail: aglez1952@gmail.com
To evaluate the effect of 200 IU of PMSG on reproductive behaviour of hair sheep ewes were bred by 1) intrauterine artificial insemination by laparoscopy (IAIL) or 2) natural mount (NM) in Northeast Mexico, and subjected to an estrus synchronization protocol, with fluorogestone acetate sponges for 10 d (40 mg, FGA). Twenty four hours before sponge withdrawal, the ewes were randomly assigned to one of two treatments, T1= 200 IU of PMSG (n= 40) IM or T2= 0 IU of PMSG (n=20). Ewes showing estrus, were divided in two groups, to be served by 1) MN or 2) by IAIL. The PMSG treatment reduced (P<0.0001) hours to estrus (HE) (25.8 h vs 37.7 h). The conception rate (CR) was smaller (P<0.05) in the PMSG treated ewes. In addition, the lambing rate (LR) and the fecundity (Fc) were smaller (P<0.05) in the ewes of the control group. The CR was lesser (P<0.05) for the IAIL group. The LR was lesser (P<0.05) in the ewes of the NM group. PMSG reduced the hours to estrus and increased the lambing rate; however, it will be necessary to determine the effect of PMSG dose, on the reproductive efficiency of the ewes. It is recommended to use an FGA+PMSG treatment for inducing the estrus, accompanied with IAIL to increase reproductive rate in hair sheep ewes.
Hair sheep, PMSG, mounting, intrauterine insemination, prolificacy
